Video: James Costello, who was injured in the Boston Marathon bombing, fell in love with nurse Krista D’Agostino, to whom he is now engaged. He tells TODAY that he was “glad I got blown up,” so that he could meet the love of his life.

Boston Marathon bombing victim James Costello believes the worst moment of his life was a blessing in disguise.

Being injured in the April 15 attack led Costello, 31, to meet his future bride, Krista D’Agostino, while she was working a six-week temporary stint as a traveling nurse at Spaulding Rehabilitation Hospital. He was transferred there after undergoing multiple surgeries over two weeks at Massachusetts General Hospital, and the two began a relationship that culminated in a wedding proposal in France during a recent 10-day trip.

"One thing that she hates that I always say is I’m actually glad I got blown up,'' Costello told Savannah Guthrie on TODAY Friday. "I wish everyone else didn’t have to, but I don’t think I would have ever met her if I didn’t, so I’m pretty happy."

"I do hate when he says that,'' a smiling D'Agostino told Guthrie.

After they met, Costello asked D'Agostino to accompany him to a benefit for the bombing victims, and the couple became inseparable over the ensuing eight months. Costello then proposed to D'Agostino earlier this week during a 10-day trip to France, part of an all-expenses-paid “Heroes Cruise”with a total of 114 first responders, their families, and victims of the bombing, courtesy of Boston-based Vantage Deluxe World Travel.

“I now realized why I was involved in the tragedy," Costello wrote on Facebook. "It was to meet my best friend, and the love of my life. Eight months later I’m happy to announce that we will spend the rest of our lives together."

Costello's story of finding love after tragedy touched people across the world, who recognized him as the subject of one of the most widely viewed images in the wake of the blast. A photographer captured Costello staggering through the streets with his clothes shredded and his legs burned. That image now stands in dramatic contrast to the picture he posted on Facebook of D'Agostino flashing her new engagement ring in front of a Ferris wheel in Lyon, France.

Kenshin Okubo / AP

In this photo provided by The Daily Free Press and photographer Kenshin Okubo, Boston Marathon bombing victim James Costello staggers away in his torn clothing from the finish area in Boston, Monday, April 15, 2013.

"I think we’re surprised,'' he said. "We wanted this reaction for our friends and family. We didn’t know it was going to be the whole world."

At the moment the bomb went off, Costello had been walking toward the Boston Marathon's finish line with five of his friends to cheer on others. Three of those friends each lost a leg; the others suffered extensive burns and shrapnel wounds. Costello underwent multiple surgeries, including several skin grafts, and then met D'Agostino during his recovery.

"I had noticed her in passing, and shortly after that she came into my room to cover a lunch break and change the dressing on my leg, and still no thoughts of (romance),'' Costello said. "Then, after we realized we had some mutual friends, we started talking, and I invited her to a benefit."